The Auto Charge 12 HO, Model 091-170, is a high output fully automatic
battery charger for vehicles with a single battery system. A patented
"Sample & Hold" circuit is utilized to detect the actual battery
voltage. This eliminates the error due to the current flowing in the
charging wires and assures that the battery is charged to the precise
float voltage. A current limiter prevents overloading the charger when
charging a deeply discharged battery or driving large parasitic loads.
The charger is ruggedly constructed to assure reliable operation when
mounted in a vehicle.

20A, 12V charge rating

Automatic operation regulates output to a single battery bank

A
patented built in sense circuit, checks battery voltage 120 times per
second, to compensate for voltage drop in charging wires providing
quick recharge, with no overcharge